Automatic commutator-adjuster



(No Model.)

BL THOMSON.

AUTOMATIC COMMUTATOR ADJUSTER.

No. 363,184. Patented May 17,1887.

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flNVENTOR f% %W72JM WITNESSES A TTORNEYJ UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF LYNN, MASSACHUSETTS.

AUTOMATIC COMMUTATOR-ADJUSTER.

SPECIFICATION forming part of Letters Patent 110,363,184, dated May 17, 1887.

Application filed August 25, 1886. Serial No. 211,856. (No model.)

To all whon't it nmyconcern: 1

V Be it known that I, ELIHU THOMSON, a cilizen of the United States, and a resident of Lynn, in the county of Essex and State of Massachusetts, have invented a certain new and useful Automatic Gommutator-Adj uster, of which the following is a specification.

The object of the present invention is to effect an adjustment of the commutators of a machine used for supplying currents to resistances-such as incandescent lamps in multiple arc whose number may be variedand to effeet the adjustment in such way as will cause the brushes to follow the changes in the neutral line by steps orjumps of few or greater number, according to the construction and use of the apparatus. J

It is often the case in operating dynamoelectrie machines of improved type that there is no necessity, or very little necessity, for-the adjustment of the commutator until the load reaches a determined amount, or until the current delivered hasexceeded a certain limit, in which cases an adjustment may be quickly made, which will be good up to the limit of. capacity of the apparatus. On taking off the load the same will be'trne, but in the reverse way. In other cases and with different apparatus it will be necessary to make agraduated or step by-step adjustment of the commutator in order to secure the best results. It isthis graduated or step-by-step adjustment of the commutator which is the object of the present invention.

To this end my invention consists, gener ally speaking, in mounting the brushes upon a holder movable around the axis of the commutator and armature of the machine, a definite movement of revolution being given to the holder and brushes in the direction of revolution of the commutator and armature upon a determinate increase of current yield or load by means of an armature or equivalent portion of a translating deviccsuch as an electromagnet-which armature is subjected to a continued pull by the influence of the magnet, and moves with the commutator-brushes through a series of consecutive steps of adjustment.

The drawings filed with the present case illustrate one way of carrying my said invention into effect by causing the piovement of armature of an electro-magnet located upon .the main circuit, or in a part thereof, or in a t branch from the same. It is evident, however, that the general purpose of my invcniion may be attained in other Ways.

In the accompanying drawings, Figure l is a general view of one form of apparatus for carrying my invention into effect. Fig.2 is an enlarged view oft-he electromagnet and eontrolling-armature with the circuit connections thereof. Fig. 3 showsamodified form of electro-magnet and armature. I

Referring to Fig. 1, B B indicate the adjustable brushes and holders movable around the axisX of the commutator of a dynamoelectric machine. Such machine may have a derived-circuit field, as indicated at F, its main current being fed to the lights L L in multiple are (or other similar resistances) in varying numbers, or the machine may be compound wound or otherwise. In the main circuit, or in a part of it, or in a branch from the same, is an electro-magnet, M, of pro longed pulling power. The armature N, mounted upon a support, B, gives movement to the holder and brushes through the connecting-links J J. The armature is held rctraeted by the spring S when no current is on.

The helix of the magnet M is made up of several coils of wire of progressively larger diameter, beginning with a coil of fine wire next the armature end up to a large wireat the other end, which will carry the full current to which the apparatus is to respond. These coils are in series, from the finest to the coarsest, in regular order, the ends being connectcdinto the circuit, as 00 and y. From the junction of the adjacent coils a connection is taken to one of a series of contacts, 1 2 3, traversed by asliding contact connected to lever Y, and indicated at I. The sliding contact I is controlled by an attachment, D, from the armature-lever A of the armature N.

\Vhen the armature is fully retracted, all

the coils-of which the magnet M is made up from X to Y are in circuit and traversed by the current.

' The operation of the device is as follows: An increase of currentyield or load causes the armature N to be drawn down, thereby giving motion to the movable holders and brushes,

the holder and brushes tobc controlled by the j Then a definite movement of the armature N has taken place, the sliding contact I, controlled thereby, reaches the contact 1, thereby shunting the fine-wire coil from the circuit, whereupon the furthermovement of the armature N is arrested until a considerable further increase of current yield or load, when a further movement occurs and the next finest wire is shunted at 2, and so on until only the last coarse coil is left unshuntcd. I thus secure a magnet which will respond to variations of current from two to three units up to one hundred to two hundred units by virtue of the increasing section and decreasing convolutions brought into action as the current is on and the lessening section and increasing convolutions when the current is diminished.

It is evident that the desired variations in the strength of the magnet M may be produced in other ways besides shunting definitelengths ofwire of the magnet-coil. Thus I may attain the same object by causing the determinate changes in the current yield to cutout certain definite lengths of wire successively, or the reverse upon the decrease of the current; or I may cause these changes of current yield to reverse the direction of the current in definite lengths of wire, the general purpose being merely to increase or decrease the strength of the magnet M a definite amount upon determinate changes of current yield or load. It is evident that this arrangement is useful for other purposes beside commutator ad j ustment, and may be applied to any case where larger variations of current are to be applied to effect graduated movements.

In the modified form of my invention shown in Fig. 3 the magnet M is axial, and the core N is provided with a part, J, for attachment to the movable holder and brushes, and a part, P, suitably constructed to successively pick up the restrailung-weights \V W IV as the increasing load or strength of current causes the core N to be drawn into the magnet-coil M, thus giving a regular increase of restraining power, whose effects may be varied by changing the relative size and position of the weights so lifted by the core. It is evident that the axial magnet in this illustration can be replaced by magnets with prolonged pulling power with restraining forces of greatlyincreased amounts, the purpose of each arrangement being to give to the commutatorbrushes upon increase of load a number of successive readj ustments due to the increased effects of the current in the coils of N, which respond to variations in the main current, whose main varies very greatly under different conditions of load.

I do not claim in this application giving to the commutator of a dynamo-machine a single adjustment, as that invention is the subject of another application; but

lVh-at I claim as my invention is 1. The combination, with a dynamomachine whose eurrent yield or load varies within wide limits, of a movable commutator, an elcc' tro-maguet and armature responding to determinate changes in current yield or load, and means whereby said armature may impart a corresponding step-by-stcp movement to the commutator, said armature being in continued connection with the commutator-Snpport and exerting a continued pull on the samethrough a series of consecutive changes of position.

2. The combination, with a dynamo machine whose current yield or load varies within wide limits,'of an armature, an electromagnet of prolonged'pulling power, and means whereby determinate changes of such current yield antomaticall y ei't'ect corresponding changes in the power of such magnet in the reverse sense, thereby giving a step-by-step movement to such armature, as and for the purpose set forth.

3. The combination, with a dynamo-machine whose current yield orload varies within widelimits, of an armature, an electro-magnet of prolonged pullin g power, and means w hereby definite lengths of wire may be shunted in or out of the coil of the magnet upon determinate changes in the current yield 01' load, thereby imparting a step-bystep movement to the armature, as and for the purpose described.

4. The combination, with a dynamo-machine whose current yield or load varies within widelimits, ofa movable commutator, an elec tro'magnet of prolonged pulling power, an armature, and means whereby definite lengths of wire may be shunted in or out of the coil of the magnet upon determinate changes of current yield or load, whereby said armature may impart a step-bystep movement to the commutator, as and for the purpose described.

5. The combination, with a dynamo-machine whose current yield or load varies within wide limits, of an armature, an electromagnet of prolonged pulling power whose helix is composed of sections of wire of progressively larger or smaller diameter arranged in series, and means whereby such sections may be successively shunted in or out of eircui t upon determinate changes of current yield or work, thereby imparting a step-bystep movement to the armature, as and for the purpose described.

6. The combination, with a dynamo -machine whose currentyield or load varies within wide limits, of an clectro-magnet or other translator of electric energy responding to determinate ehanges in such current yield or load, and imparting a graduated movement to the armature or corresponding part that is constantly within the attractive influence of such magnet or translator through a series of consecutive changes of position, as and for the purpose described.

Signed at Lynn, in the county of Essex and State of lllassachusetts, this 19th day of August, A. D. 1886.

ELII-I'U' THOMSON.

"Wi tnesscs:

J. W. GInnoNnY, E. WILBUR Bren, Jr, 

